NAME

       sd - driver for SCSI disk drives

SYNOPSIS

       #include <linux/hdreg.h>        /* for HDIO_GETGEO */
       #include <linux/fs.h>           /* for BLKGETSIZE and BLKRRPART */

CONFIGURATION

       The  block device name has the following form: sdlp, where l is a letter denoting the physical drive, and
       p is a number denoting the partition on that physical drive.  Often, the partition  number,  p,  will  be
       left off when the device corresponds to the whole drive.

       SCSI  disks  have a major device number of 8, and a minor device number of the form (16 * drive_number) +
       partition_number, where drive_number is the number of the physical  drive  in  order  of  detection,  and
       partition_number is as follows:

       partition 0 is the whole drive
       partitions 1-4 are the DOS "primary" partitions
       partitions 5-8 are the DOS "extended" (or "logical") partitions

       For  example,  /dev/sda  will have major 8, minor 0, and will refer to all of the first SCSI drive in the
       system; and /dev/sdb3 will have major 8, minor 19, and will refer to the third DOS "primary" partition on
       the second SCSI drive in the system.

       At this time, only block devices are provided.  Raw devices have not yet been implemented.

DESCRIPTION

       The following ioctls are provided:

       HDIO_GETGEO
              Returns the BIOS disk parameters in the following structure:

                  struct hd_geometry {
                      unsigned char  heads;
                      unsigned char  sectors;
                      unsigned short cylinders;
                      unsigned long  start;
                  };

              A pointer to this structure is passed as the ioctl(2) parameter.

              The  information returned in the parameter is the disk geometry of the drive as understood by DOS!
              This geometry is not the physical geometry of the drive.  It is used when constructing the drive's
              partition  table,  however,  and  is  needed  for convenient operation of fdisk(1), efdisk(1), and
              lilo(1).  If the geometry information is not available, zero will  be  returned  for  all  of  the
              parameters.

       BLKGETSIZE
              Returns the device size in sectors.  The ioctl(2) parameter should be a pointer to a long.

       BLKRRPART
              Forces a reread of the SCSI disk partition tables.  No parameter is needed.

              The SCSI ioctl(2) operations are also supported.  If the ioctl(2) parameter is required, and it is
              NULL, then ioctl(2) will fail with the error EINVAL.

FILES

       /dev/sd[a-h]: the whole device
       /dev/sd[a-h][0-8]: individual block partitions

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.